Defining the Default Mode with the setFetchMode() Method

The setFetchMode() method allows you to pre-define the format in which you want to receive data from the database for a specific statement. Instead of writing PDO::FETCH_ASSOC or PDO::FETCH_OBJ inside every single fetch() call, you configure it once for the entire result set. This makes your code shorter, cleaner, and much easier to maintain.

EXAMPLE

<?php
class Database {
    private $server = "localhost";
    private $username = "root";
    private $password = "";
    private $db_name = "pdo_db";
    public $connection;

    public function __construct() {
        try {
            // Added charset=utf8mb4 for character support
            $dsn = "mysql:host=" . $this->server . ";dbname=" . $this->db_name . ";charset=utf8mb4";
            $this->connection = new PDO($dsn, $this->username, $this->password);
            $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        } catch(PDOException $e) {
            die("Connection failed: " . $e->getMessage());
        }
    }

    public function getUser($id) {
        $statement = $this->connection->prepare("SELECT first_name FROM users WHERE id = :id");
        $statement->execute(['id' => $id]);

        // Set the default mode to an associative array
        $statement->setFetchMode(PDO::FETCH_ASSOC);

        // Now fetch() does not require any additional parameters
        return $statement->fetch();
    }
}

// PART 3: Usage
$db = new Database();
$u = $db->getUser(1);
echo "User: " . $u['first_name'];
?>

RESULT

The result will be displayed here...

Practical Application: This method is most commonly applied immediately after preparing or executing a query to guarantee data consistency throughout the processing lifecycle. Check the process at home by following these steps:

Start the Apache and MySQL modules in the XAMPP control panel.
Ensure that the users table exists and contains at least one record within the pdo_db database.
The method accepts a constant, such as PDO::FETCH_ASSOC (array) or PDO::FETCH_OBJ (object).
Insert the example below into a PHP file and observe how clean the fetch call looks without any additional parameters.